1. Field of the Invention
The invention herein disclosed relates to supports for rotors and motors in fan assemblies, and configurations thereof allowing access to the different parts of the assemblies in order to perform maintenance operations.
2. Background Art
Assemblies that couple motors and fans are generally used in the industrial field, mainly in devices such as agitators, blowers, impellers or turbines. These devices have in common the characteristics of mixing, separating or simply controlling the flow of a fluid through a confined space. Depending on the nature of the fluids circulating through the fans blades, the assemblies will be designed in order to provide maximum efficiency and to facilitate maintenance.
Several designs among those encountered in the art have aimed at providing an ergonomic embodiment for fan and motor assemblies, allowing an easy access to their components, mainly the fan, the motor and the casing thereof, for facilitating maintenance.
One such design is described in U.S. Pat. No. 4,092,088, issued to Nemesi on May 30, 1978. It discloses a centrifugal fan and motor assembly housed in a casing intended to be coupled into a ducting network. The fan and motor assembly is attached to a removable door; the latter is bolted to the casing. When the fan and motor assembly is unbolted from the casing, it can either remain attached to the casing, resting on the lower cutting edge of the opening thereof, or be completely removed from the casing. This latter operation is carried out by lifting the assembly in order to disengage it from the casing, then pulling the assembly out of the casing. This configuration involves mechanical lifting equipment (e.g., a crane) or specific manpower, thus making this fan assembly inefficient.
U.S. Pat. No. 5,185,941, issued to Dongelmans on Feb. 16, 1998, describes a blower-cleanout door assembly. The assembly, consisting of a blower wheel and a motor, is mounted on a swing-out door. The door panel is equipped with a support that carries the blower assembly. When the door is closed, the assembly is operational, and when the door is swung open, it is possible to perform maintenance operations on the blower wheel or on the motor. The blower assembly of this reference is generally designed to provide an easy access to the blower wheel in order to facilitate the cleaning of both the blower wheel and the blower interior.
In this assembly, the door is pivotally mounted on the blower housing such that all the weight of the assembly rests upon two hinges located on each side of the door panel.
This design is therefore unfavourable to heavy assemblies because the hinge bars may crack or break over time, or if the loads applied upon them exceed their mechanical resistance. Moreover, the fluid circulating through the blower housing may corrode the hinge mechanism, especially if the fluid is humid or contains a corroding gas or liquid. These factors reduce the efficiency of such pivotally mounted structures and only allow a certain range of weight that can be sustained by the pivotally mounted door.
It is pointed out that the assemblies of the above-cited references may be subject to failure or extended periods of downtime due to the above-described reasons. Such fan assemblies are often associated with industrial processes whose productivity is affected by the downtime of the fan assembly.
It would be highly desirable to provide a fan assembly that allows maintenance operations to be performed safely, quickly and at low costs. Since the weight of the assemblies encountered in the art can vary from light to very heavy, there is a need for support assemblies that do not impede the efficiency of maintenance operations.